Fibrillation jet

ABSTRACT

There is provided an improved forwarding jet especially useful where a fibrillatable tape is to be subjected to the action of at least four fluid twisting means. This apparatus is comprised of a housing having a tubular passageway therethrough for the passage of a fibrillatable tape and a fluid manifold for the delivery of pressurized fluid to said tubular passageway. Said tubular passageway is comprised of at least two spaced apart bores of common axis, each of said bores having a fluid passageway tangentially intersecting it at an angle of from about 15* to about 70* with respect to the common axis of said bores. The tangential intersection of the bores is of opposite incidence so that the direction of twist imparted to the tape is reversed between adjacent bores.

United States Patent 91 [451 Apr. 17, 1973 Gibbon F IBRILLATION JET [75]Inventor: John D. Gibbon, Charlotte, NC.

[73] Assignee: Fiber Industries, Inc.

[22] Filed: Mar. 31, 1971 [21] Appl. No.: 129,738

Related US. Application Data [63] Continuation-impart of Ser. No.70,713, Sept. 9,

[56] References Cited UNITED STATES PATENTS 2/1967 Pitzl ..57/157 F UX1/1964 Breen et a1. ..57/34 B UX FOREIGN PATENTS OR APPLICATIONS 864,6954/1961 Great Britain ..57/34 B 6,912,566 2/1970 Netherlands ..57/34 BPrimaryExaminer-Donald E. Watkins Attorney-Thomas J. Morgan, S. D.Murphy and H. J. Greenwald [57] ABSTRACT There is provided an improvedforwarding jet especially useful where a fibrillatable tape is to besubjected to the action of at least four fluid twisting means. Thisapparatus is comprised of a housing having a tubular passagewaytherethrough for the passage of a fibrillatable tape and a fluidmanifold for the delivery of pressurized fluid to said tubularpassageway. Said tubular passageway is comprised of at least two spacedapart bores of common axis, each of said bores having a fluid passagewaytangentially intersecting it at an angle of from about 15 to about 70with respect to the common axis of said bores. The tangentialintersection of the bores is of opposite incidence so that the directionof twist imparted to the tape is reversed between adjacent bores.

8 Claim, 3 Drawing Figures PATENTEDAFR 1 7197s FIG. 3

FIG. 2

' INVENTOR JOHN D. GIBBON BY & 2 v

FIBRILLATION JET This is a continuation-in-part of US. application Ser.No. 70,713 (filed Sept. 9, 1970).

As is disclosed in applicants copending application Ser. No. 70,713, aneconomical process for fibrillating a fibrilla-table tape comprises thestep of subjecting a travelling fibrillatable tape under a tension offrom about 0.05 to about 0.2 grams per denier to the action of at leastfour fluid twisting means wherein the direction of twist imparted to thetape is completely reversed between adjacent twisting means; the use ofthe tension on the tape insures good fibrillation.

When prior art fluid twisting means are used, there is a tension lossbetween adjacent twisting means. Thus, e.g., when the jets disclosed inNew Zealand Pat. No. 149,327 and U. S. abandoned application Ser. No.563,234 are used in the process of application Ser. No. 70,713, thetension loss encountered in one jet is sufiicient to put the tension inthe second jet outside of the range of satisfactory operation. Thistension loss may be overcome by technically complex and expensivedevices; this, however, is not desirable.

It is thus an object of this invention to provide an improvedfibrillation jet wherein the aforementioned tension loss does not occurso that two or more of said jets may be used on a single threadlinewithout the need for costly devices to correct for tension loss. Inaccordance with this invention, there is provided a forwarding jetcomprised of a housing having a tubular passageway therethrough for thepassage of a fibrillatable tape and a fluid manifold for the delivery ofpressurized fluid to said tubular passageway, said tubular passagewaycomprising at least two spaced apart bores of common axis with each ofsaid bores having a fluid passageway intersecting it at an angle of fromabout 15 to about 70 with respect to the common axis of said bores, saidintersection being at a tangent to said bores so as to impart arotational motion to fluid exhausting into said bores, said tangentialintersection being of opposite incidence in each succeeding bore therebyreversing the rotational motion in adjacent bores.

The jet of this invention is comprised of a housing having a tubularpassageway therethrough. The tubular passageway need not be cylindrical;thus, e.g., an oval shaped passageway is within the scope of thisinvention. It is preferred, however, that the tubular passageway becylindrical.

The tubular passageway is comprised of at least two coaxial bores; thesebores do not communicate with each other. In each jet it is preferredthat there be only two bores and that they each have the same diameterif they are cylindrical. It is also preferred that the bores have aperimeter of at least 3 millimeters apiece and that adjacent bores notbe more than about 3 inches apart (as measured from center-point tocenterpoint); it is more preferred that the bores have a perimeter offrom about 5 to about 20 millimeters and that adjacent bores not be morethan about 1 inch apart.

Each of the bores is tangentially intersected by a fluid passageway atan angle of from about to about 70 with respect to the common axis ofsaid bores, said tangential intersection being of opposite incidence'ineach succeeding bore (thereby reversing the rotational motion inadjacent bores). It is preferred that the angle formed by said fluidpassageway with respect to said common axis be from about 30 to about60, and it is more preferred that said angle be from about 45 to about60.

It is preferred that the perimeter of each of the fluid passageways beat least 0.5 millimeters, and it is more preferred that said perimeterbe from about 1.25 to about 10 millimeters.

In the preferred fibrillation process utilizing the jets of the instantinvention, it is preferred that the ratio of the fibrillatable tapeperimeter/bore perimeter be from about 0.1 to 1.5 (and preferably fromabout 0.3 to about 0.7) and that, when both the bores and fluidpassageways are cylindrical, the ratio of the bore diameter/fluidpassageway diameter be from about 0.1 to about 0.7 (and most preferablyfrom about 0.2 to about 0.5

The fluid used in the jet of the instant invention may be virtually anygas which approaches ideal gas behavior and does not react with the tapeto be fibrillated. Thus, e.g., air, steam, nitrogen, oxygen, carbondioxide, etc. may be used in said process; because it is one of thecheapest gases, it is preferred to use air as said fluid. When said jetis used in the aforementioned fibrillation process, the fluid velocityshould reach from about 0.5 to about 1.0 sonic velocity at the point ofcontact with the strand in each bore.

It is preferred to utilize at least two of the jets of the instantinvention to fibrillate a fibrillatable tape. When this is done thedistance between each jet should be as great as is practical; thus,e.g., two such jets may be from about 1 to about 1,000 inches apart. Itis preferred that the two adjacent jets be from about 1 to about 500inches apart, and it is more preferred that they be from about 1 toabout 72 inches apart.

The jets of this invention maintain the fibrillatable tape under atension of from about 0.05 to about 0.2 grams per denier, therebyinsuring good fibrillation. The preferred tension is from about 0.05 toabout 0.15 grams per denier, and the most preferred tension is about 0.1 grams per denier.

In the fibrillation process using at least two of the jets of thisinvention, air (or another suitable fluid) is supplied to each of thejets at a pressure of from about 10 to about 250 p.s.i.g. The preferredpressure is from about 20 to about 100 p.s.i.g., and most preferredpressure is from about 40 to about 80 p.s.i.g.

Reference to FIGS. 1, 2, and 3 will illustrate one of the preferredembodiments of applicants invention.

FIG. 1 shows one of applicant's preferred fibrillation apparatuses.FIGS. 2 and 3 are cross-sectional views of the apparatus of FIG. 1, FIG.2 being the view along line 22 and FIG. 3 being the view along line 3-3.Apparatus 10 is comprised of a U-shaped member with coaxial bores 12 and14 respectively; in applicants apparatus it is preferred thatthe housingbe comprised of at least one tape string up slot (such as slots 16 and18) for each of the bores. Fluid is supplied to manifold box 20 byconnector 22 (which is supplied with a pressurized fluid such as, e.g.,water or air), and this fluid then passes through fluid passageways 24and 26 into bores 12 and 14 respectively. Said fluid passageways areessentially tangential to bores 12 and 14, and they intersect said boresat an angle of from about 15 to about degrees with respect to the commonaxis of said bores; they are positioned in bores 12 and 14 so asEXAMPLES EXAMPLE Poly(ethylene terephthalate) with an intrinsicviscosity of 0.61 and 2 percent (by weight of polyethyleneterephthalate) of polypropylene with a melt flowindex of 15 were mixedand then subjected in a pack to a shear force of 120 sec for about 1second and extruded via a pack through a slit die (1 inch-X 0.0005inch); the extrusion temperature was 280 centigrade. The extruded tapewas quenched in water and spun. The spun tape was 10 mm wide and had atotal spun denier of 3150. The spun tape was then drawn in a first stageat a draw temperature of about 110 centigrade and a draw speed of 175feet per minute to a draw ratio of 3.5/1, and thereafter it was drawn ina second stage at a drawtemperature of about 200 centigrade and a drawspeed of 120 feet per minute to a draw ratio of 1.4/1.

This tape was then fibrillated with one of the fibrillation apparatusesof the instant invention (comprising two fluid twisting means whereinthe direction of twist imparted to the tape is completely reversedbetween adjacent twisting means) and two of said fibrillationapparatuses (hereinafter referred to as jets). The maximum speedsonecould use to get any given degree of fibrillation with one jet andtwo jets operated'at the same conditions are shown below.

Number of Fils/ Maximum Speed One Maximum Speed Q're Tape Can Use withOne Can Use with Two .let to obtain the Jets to Obtain the SpecifiedDegree Specified Degree of Fibrillation of Fibrillation (Feet/Minute)(Feet/Minute) (i.c., at no speed could the one jet give one this degreeof fibrillation) 50 0 I70 40 70 300 35 I30 410 30 230 greater than 60025 500 greater than 600 EXAMPLE 2 .A poly(ethylene terephthalate) tapewas prepared in substantial accordance with the procedure described inExample 1, with the exception that the first stage draw ratio was 3.6/1,the first stage take-up speed was 1,080 feet per minute, the first stagedraw temperature was 127 centigrade, the second stage draw ratio was1.3/1, and the second stage take-up speed was the same speed as thefibrillation speed. The tape was comprised of poly(ethyleneterephthalate) with an intrinsic viscosity of 0.61 and 2 percentpolypropylene with a melt flow index of 15.

This tape was then fibrillated with one jet and two.

jets. The results are presented below.

Number of Fils/ Maximum Speed One Maximum SpeedOne Tape Can Use with OneCan Use with Two Jet to Obtain the Jets to Obtain the Specified DegreeSpecified Degree of Fibrillation of Fibrillation (Feet/Minute)(Feet/Minute 30 650 greater than 2000 This example differs from Example1 in that the tape was prepared at much higher drawing speeds; thiseffect increases the fibrillation for a given speed through a the jetsand at the higher speeds make the fibrillation less sensitive to changesin speed.

It was observed that the use'of the two jets decrease the number oflarge filaments, thus contributing to the uniformity of the yarn. Toquantify this observation the cross sections made for Example 2 wereexamined and the number of fils with a breadth to thickness ratiogreater than 6 were tabulated. On averaging, the following results wereobtained.

Wide Fil Count (Average) l jet 2 jets Temp. of 4.5 2.2 Speed effectaveraged Hot Plate, I70 2.2 C 200 0.6 1 Speed 400 3.8 0.6 Temperatureeffects 800 4.0 1.6 average fpm 1200 3.8 2.0 1600 5.0 2.2 Overallaverage 3.7 1.5 Temp & speed effects Total averaged This experimentshows that the addition of the second jet is very effective in reducingthe number of wide fils. Another effective method of reducing wide filsis to increase the hot plate temperature to 200 centigrade. With the useof two jets and a hot plate temperature of 200 centigrade, the incidenceof wide fils was almost eliminated.

EXAMPLE 3 units are in deciliters/gram. Measurements may be made ofrelative viscosity (on an 8 percent solution polyester inorthochlorophenol) and converted to intrinsic viscosity by an empiricalformula. The tape was 8 mm wide and had a total spun denier of 4,000.The draw ratio used was 5/1 and the draw speed was 1,500 feet perminute. The tape was fibrillated with one jet and two jets, and theresults are shown below.

Although the above examples and descriptions of this invention have beenvery specifically illustrated, many other modifications will suggestthemselves to those skilled in the art upon a reading of thisdisclosure. These are intended to be comprehended within the scope ofthis invention.

What is claimed is l. A forwarding jet comprised of a housing having atubular passageway therethrough for the passage of a flbrillatable tapeand a fluid manifold for the delivery of pressurized fluid to saidtubular passageway, said tubular passageway comprising at least twospaced apart bores of common axis with each of said bores having a fluidpassageway intersecting it at an angle of from about to about 70 withrespect to the common axis of said bores, said intersection being at atangent to said bores so as to impart a rotational motion to fluidexhausting into said bores, said tangential intersection being ofopposite incidence in each succeeding bore thereby reversing therotational motion in adjacent bores.

2. The jet of claim 1, wherein each of said bores has a perimeter of atleast 3 millimeters and each of said fluid passageways has a perimeterof at least 0.5 millimeters.

3. The jet of claim 1, wherein the centerpoint of each of said bores isno further than about 3 inches away from the centerpoint(s) of itsadjacent bore(s).

4. The jet of claim 1, wherein said housing is comprised of at least onetape string up slot for each of said bores, said tape string up slotscommunicating with said bores.

5. The jet of claim 1, wherein said tubular passageway is comprised oftwo of said bores.

6. The jet of claim 5, wherein:

a. said bores are cylindrical;

b. each of said bores has a perimeter of at least 3 millimeters, andeach of said fluid passageways has a perimeter of at least 0.5millimeters; 1

c. the centerpoint of each of said boreslis no'further than about 3inches away from the centerpoint of the adjacent bore; and

d. said housing is comprised of one tape string up slot for each of saidbores, said string up slots communicating with said bores.

7. The jet of claim 6, wherein: a a. said fluid passageways intersectsaid bores at an angle of from about 30 to about with respect to saidcommon axis of said bores;

b. said bores have the same diameter; and

c. each of said bores has a perimeter of from about 5 to about 20millimeters, and each of said fluid I passageways has a perimeter offrom about 1.25 to about 10 millimeters.

8. The jet of claim 7, wherein:

a. the centerpoints of each of said bores are no further apart thanabout 1 inch, and

b; said fluid passageways intersect said bores at an angle of from about45 to about 60 with respect to said common axis of said bores.

1. A forwarding jet comprised of a housing having a tubular passagewaytherethrough for the passage of a fibrillatable tape and a fluidmanifold for the delivery of pressurized fluid to said tubularpassageway, said tubular passageway comprising at least two spaced apartbores of common axis with each of said bores having a fluid passagewayintersecting it at an angle of from about 15* to about 70* with respectto the common axis of said bores, said intersection being at a tangentto said bores so as to impart a rotational motion to fluid exhaustinginto said bores, said tangential intersection being of oppositeincidence in each succeeding bore thereby reversing the rotationalmotion in adjacent bores.
 2. The jet of claim 1, wherein each of saidbores has a perimeter of at least 3 millimeters and each of said fluidpassageways has a perimeter of at least 0.5 millimeters.
 3. The jet ofclaim 1, wherein the centerpoint of each of said bores is no furtherthan about 3 inches away from the centerpoint(s) of its adjacentbore(s).
 4. The jet of claim 1, wherein said housing is comprised of atleast one tape string up slot for each of said bores, said tape stringup slots communicating with said bores.
 5. The jet of claim 1, whereinsaid tubular passageway is comprised of two of said bores.
 6. The jet ofclaim 5, wherein: a. said bores are cylindrical; b. each of said boreshas a perimeter of at least 3 millimeters, and each of said fluidpassageways has a perimeter of at least 0.5 millimeters; c. thecenterpoint of each of said bores is no further than about 3 inches awayfrom the centerpoint of the adjacent bore; and d. said housing iscomprised of one tape string up slot for each of said bores, said stringup slots communicating with said bores.
 7. The jet of claim 6, wherein:a. said fluid passageways intersect said bores at an angle of from about30* to about 60* with respect to said common axis of said bores; b. saidbores have the same diameter; and c. each of said bores has a perimeterof from about 5 to about 20 millimeters, and each of said fluidpassageways has a perimeter of from about 1.25 to about 10 millimeters.8. The jet of claim 7, wherein: a. the centerpoints of each of saidbores are no further apart than about 1 inch, and b. said fluidpassageways intersect said bores at an angle of from about 45* to about60* with respect to said common axis of said bores.